Improvement in hot-air engines



T..MODONOUGH.

HOT AIR ENGINE.

No. 44,966. Patented Nov. 8, 1864.

f2, 6. aaywfaw UNITED STATES PATENT OFFICE.

THOMAS MODONOUGH, OF 'MIDD LETOWN.' CONNECTICUT.

IMPROVEMENT IN HOT-AIR ENGINES.

Specification forming part of Letters Patent No.- 44 ,966, dated November 8, 1864.

To all whom it may concern:-

Be it known that I, THOMAS MCDONOUGH, ofMiddletow-n, in the county of Middlesex, in the State of Connecticut, have invented a new and useful combination of improvements inthe "caloric-engine; and I do herebydeclareat onnd the-furnace and exposed to its heat.

Their lower ends are open to cold air to enter them. Their upper endsopen into ahot chamber-,cr, above the furnace. These pipes are used to heat the air as it passes-amongthe wires and into the chamber 0 c. A valve-chest containing two valves, 1; and o ,is connected by one passage with the chamber 0 c, and also by a passage with the lower part of the cylinder of the engine, so that the hot-air may be drawn past the valve 1) into the lower part of the cylinder whenever vthe plunger Pl is raised, and may also be moved past the valve o into the passage that leads from the valve chest toward the upper part of the cylinder whenever the plunger Pl is lowered. These valves are opened and shut by any usual method of working puppet-valves.

Sheets of metal soldered or braced together at their edges and corrugated, as shown in the siction z, are connected a tone part to a passage leading from the valve-chest, and at another part to the passage leading to the upper part of the cylinder, so that the air in moving from the lower part of the cylinder past the valve 21 must pass between these sheests c p, and thus be cooled before cnterin g the upper part of the cylinder 01'.-

A valve, En, opening outward, is. 'attachcd to the upper-part ofthe cylinder Or to discharge the air when the plunger is raised.

The valve 1: being shut, prevents any other egress for it. to therQrank, and by its upward movement hot air is drawn into the lower part of the cylinder and cold. air thrown out of the upper part; then by its downward movement thehot air in the lower partismoved pastthe valve '0 through GP,-that is, between the sheetsinto the upper part, where its tension is less and-volume the same as in the lower part, so

that on admitting the air from the chamber 0 0 now to press on the lower'end of the plunger Pl, it-is forced up until the cold air above'it equals in tension the hotair beneath it, and

the momentum acquired moves the plunger through the remainder of its upward stroke,

during which it discharges the cold air above it. The momentum also gives the plungerthe next downward stroke.

I am' aware that wires in heated chests have been used as regenerators for air which has first obtained its .heat by contact with plates heated directly by the tire, and next imparted it to the wires.

I am aware that thin plates are variously applied for cooling.

1 am aware that a single piston is used for the transfer of gases arising from combustion.

' I disclaim all these inventions.

I claim- The combination of the heaters and coolers scribed THOMAS MODONOUGH.

Witnesses: V

EDWARD G. PATTISON, N. (l. STOUGHTQN.

The plunger Pl is connected 

